I know, I learned a while ago, to hide power from you, I should just put it in a bookYou illiterate parasites: I kill you every time

Unintelligent people often don’t read books (which contributes to their being illiterate), so theoretically and literally if he had power to hide, he could put it in a book without having to worry about “illiterate parasites” finding it. This is likely a jab at MC’s with limited vocabulary/lyrical skills.
In summary: knowledge is power!